PROJECT SUMMARY/ABSTRACT Even as we move into the 21st century, mining accidents are still a regular occurrence, often resulting in the loss of dozens of lives. Many of these fatalities could have been averted had there been a reliable emergency communications system in place to provide life-saving information to search-and-rescue parties and to trapped miners. To address this problem, Physical Optics Corporation (POC) proposes to advance the development of our new Magnetic Through-The-Earth Miner Transceiver for Emergency Communications (MATHEMITE) System. This system is a transceiver for two-way through-the-earth (TTE) communications, which was proven feasible in Phase I by demonstrating a 375 ft TTE communication range at the Edgar Mine (Idaho Springs, CO) and at the NIOSH Experimental Mine (Pittsburgh, PA). MATHEMITE integrates a novel zero-power mine transmitter (ZPT) and communication protocol to maintain mine-to-surface communications in all emergency situations. Innovations in the mine transmitter enable maintaining a communication link with a surface receiver through more than 2000 ft of overburden with no external power or batteries required. Application of digital noise-reduction data processing allows the surface receiver to detect the unique signature arriving from the mine transmitter, amid the mine environmental noise. These advantages also make the proposed transceiver commercially attractive, since it is based largely on integration of existing technology. The potential markets for the proposed transceiver include not only mine safety but also construction and energy industries, in addition to numerous military and security applications. As a result, POC's proposed research will significantly and positively impact the safety of personnel involved in underground operations by providing a reliable, compact, through-the-earth communications system. This directly supports the mission of the National Institute for Occupational Safety and Health to improve safety and health of mining workers. In Phase I, POC successfully demonstrated the feasibility of the MATHEMITE system in mine operation with a scaled-down prototype over a 375 ft TTE communication range. The goal of Phase II is to develop and demonstrate a full-scale prototype system with a range of up to 2000 ft that is completely safe for mine use and does not require additional infrastructure. Besides the prototype development, POC will conduct extensive measurements at mine test sites to accurately characterize the mine environment, including environmental noise and interference. POC will ensure the design meets Mine Safety and Health Administration regulations. Successful development of this technology will result in an entirely new emergency communications system that will overcome the safety, reliability, power, and size issues of current mine communications technology.